Tumor necrosis factor-alpha during neonatal brain development affects anxiety- and depression-related behaviors in adult male and female mice

Cord serum cytokines at birth and children's trajectories of mood dysregulation symptoms from 3 to 8 years: The EDEN birth cohort

There is growing evidence that in utero imbalance immune activity plays a role in the development of neurodevelopmental and psychiatric disorders in children. Mood dysregulation (MD) is a debilitating transnosographic syndrome whose underlying pathophysiological mechanisms could be revealed by studying its biomarkers using the Research Domain Criteria (RDoC) model. Our aim was to study the association between the network of cord serum cytokines, and mood dysregulation trajectories in offsprings between 3 and 8 years of age. We used the data of a study nested in the French birth cohort EDEN that took place from 2003 to 2014 and followed mother-child dyads from the second trimester of pregnancy until the children were 8 years of age. The 2002 mother-child dyads were recruited from the general population through their pregnancy follow-up in two French university hospitals. 871 of them were included in the nested cohort and cord serum cytokine levels were measured at birth. Children's mood dysregulation symptoms were assessed with the Strengths and Difficulties Questionnaire Dysregulation Profile at the ages 3, 5 and 8 years in order to model their mood dysregulation trajectories. Out of the 871 participating dyads, 53% of the children were male. 2.1% of the children presented a high mood dysregulation trajectory whereas the others were considered as physiological variations. We found a significant negative association between TNF-α cord serum levels and a high mood dysregulation trajectory when considering confounding factors such as maternal depression during pregnancy (adjusted Odds Ratio (aOR) = 0.35, 95% Confidence Interval (CI) [0.18-0.67]). Immune imbalance at birth could play a role in the onset of mood dysregulation symptoms. Our findings throw new light on putative immune mechanisms implicated in the development of mood dysregulation and should lead to future animal and epidemiological studies.

Exploring the role of biologics in depression

Depression is a chronic and prevalent neuropsychiatric disorder; clinical symptoms include excessive sad mood, anhedonia, increased anxiety, disturbed sleep, and cognitive deficits. The exact etiopathogenesis of depression is not well understood. Studies have suggested that tumor necrosis factor-alpha (TNF-α) and interleukins (ILs) perform vital roles in the pathogenesis and treatment of depression. Increasing evidence suggests the upregulation of TNF-α and ILs expression in patients with depression. Therefore, biologics like TNF inhibitors (etanercept, infliximab, adalimumab) and IL inhibitors (ustekinumab) have become key compounds in the treatment of depression. Interestingly, treatment with an antidepressant has been found to decrease the TNF-α level and improve depression-like behaviors in several preclinical and clinical studies. In the current article, we have reviewed the recent findings linking TNF-α and the pathogenesis of depression proving TNF-α inhibitors as potential new therapeutic agents. Animal models and clinical studies further support that TNF-α inhibitors are effective in ameliorating depression-like behaviors. Moreover, studies showed that peripheral injection of TNF-α exhibits depressive symptoms. These symptoms have been improved by treatment with TNF-α inhibitors. Hence suggesting TNF-α inhibitors as potential new antidepressants for the management of depressive disorder.

Sex Differences in Depression Caused by Early Life Stress and Related Mechanisms

Depression is a common psychiatric disease caused by various factors, manifesting with continuous low spirits, with its precise mechanism being unclear. Early life stress (ELS) is receiving more attention as a possible cause of depression. Many studies focused on the mechanisms underlying how ELS leads to changes in sex hormones, neurotransmitters, hypothalamic pituitary adrenocortical (HPA) axis function, and epigenetics. The adverse effects of ELS on adulthood are mainly dependent on the time window when stress occurs, sex and the developmental stage when evaluating the impacts. Therefore, with regard to the exact sex differences of adult depression, we found that ELS could lead to sex-differentiated depression through multiple mechanisms, including 5-HT, sex hormone, HPA axis, and epigenetics.

Treadmill exercise sex-dependently alters susceptibility to depression-like behaviour, cytokines and BDNF in the hippocampus and prefrontal cortex of rats with sporadic Alzheimer-like disease

Alzheimer's disease (AD) is associated with increased depression-related behaviours. Previous studies have reported a greater risk of AD and depression in women. In recent years, we and others have provided evidence that exercise during life could be used as a therapeutic strategy for stress-related disorders such as depression. The main goal of the current study was to determine whether treadmill exercise during life can reduce depression-related behaviours in male and female Wistar rats with sporadic Alzheimer-like disease (ALD). Animals were subjected to treadmill exercise eight weeks before and four weeks after ALD induction by streptozocin (STZ). We measured body weight, food intake, and depression-related symptoms in rats using five behavioural tests. We measured brain-derived-neurotrophic factor (BDNF), tumour-necrosis factor (TNF)-α, and interleukin (IL)-10 levels in the hippocampus and prefrontal cortex of animals. Our findings showed that exercise but not ALD induction decreased body weight and food intake in male and female rats. ALD induction increased depression-related symptoms and hippocampal TNF-α in male and female rats. Besides, treadmill exercise alone decreased depression-related behaviours and increased hippocampal BDNF in females but not males. We also found that treadmill exercise decreased depression-related behaviours and TNF-α in the hippocampus and prefrontal cortex, and increased IL-10 in the prefrontal cortex and BDNF in the hippocampus of female ALD-induced rats. However, treadmill exercise only reduced anhedonia-like behaviour and hippocampal TNF-α in male ALD-induced rats. Overall, the evidence from this study suggests that treadmill exercise alters depression-related behaviours, brain BDNF and cytokines in a sex-dependant manner in rats with sporadic Alzheimer-like disease.

Swimming exercise decreases depression-like behaviour and inflammatory cytokines in a mouse model of type 2 diabetes

NEW FINDINGS

What is the central question of this study? Can swimming exercise decrease depression-like behaviour and inflammation in type 2 diabetic mice? What is the main finding and its importance? Swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Swimming exercise might be useful for the treatment of depression-related disorders in patients with type 2 diabetes.

ABSTRACT

Clinical and experimental studies have shown that type 2 diabetes is associated with depression-related disorders. Inflammation has been identified as a common mechanism in both type 2 diabetes and depression. Several studies have suggested that swimming exercise might be able to reduce depression-related symptoms. The present study aimed to explore whether swimming exercise can decrease depression-like behaviour in type 2 diabetic mice. To induce type 2 diabetes, male C57BL6 mice were treated with a high-fat diet and streptozocin. Type 2 diabetic animals were subjected to swimming exercise for 4 weeks. Then, depression-like behaviours were evaluated by sucrose preference, novelty-suppressed feeding, social interaction and tail suspension tests. We also measured levels of glucose, insulin and pro-inflammatory cytokines such as interleukin-1β and tumour necrosis factor-α in the serum of animals. The results indicated that type 2 diabetes significantly increased anhedonia- and depression-like behaviours in mice. We also found significant increases in glucose, insulin and inflammatory cytokines in diabetic mice. Moreover, swimming exercise reduced anhedonia- and depression-like behaviour in type 2 diabetic mice. Swimming exercise also decreased glucose and inflammatory cytokines in the serum of mice with type 2 diabetes. Collectively, this study demonstrates that swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Further clinical studies are needed to validate these findings in patients with type 2 diabetes.

Tumor necrosis factor-α expression aberration of M1/M2 macrophages in adult high-functioning autism spectrum disorder

The etiology of autism spectrum disorder (ASD) is complex, and its pathobiology is characterized by enhanced inflammatory activities; however, the precise pathobiology and underlying causes of ASD remain unclear. This study was performed to identify inflammatory indicators useful for diagnosing ASD. The mRNA expression of cytokines, including tumor necrosis factor-α (TNF-α), was measured in cultured M1 and M2 macrophages from patients with ASD (n = 29) and typically developed (TD) individuals (n = 30). Additionally, TNF-α expression in the monocytes of patients with ASD (n = 7), showing aberrations in TNF-α expression in M1/M2 macrophages and TD individuals (n = 6), was measured. TNF-α expression in M1 macrophages and the TNF-α expression ratio in M1/M2 macrophages were markedly higher in patients with ASD than in TD individuals; however, this increase was not observed in M2 macrophages (M1: sensitivity = 34.5%, specificity = 96.7%, area under the curve = 0.74, positive likelihood ratio = 10.34; ratio of M1/M2: sensitivity = 55.2%, specificity = 96.7%, area under the curve = 0.79, positive likelihood ratio = 16.55). Additionally, TNF-α expression in monocytes did not significantly differ between patients with ASD and TD individuals. In conclusion, further studies on TNF-α expression in cultured macrophages may improve the understanding of ASD pathobiology. LAY SUMMARY: TNF-α expression in differentiated M1 macrophages and TNF-α expression ratio in differentiated M1/M2 macrophages were markedly higher in patients with ASD than in TD individuals, while no difference in TNF-α expression was found in pre-differentiation cells such as monocytes. These measurements allow elucidation of the novel pathobiology of ASD and can contribute to biomarker implementation for the diagnosis of adult high-functioning ASD.

Tumor Necrosis Factor Alpha Signaling and Organogenesis

Tumor necrosis factor alpha (TNF-α) plays important roles in processes such as immunomodulation, fever, inflammatory response, inhibition of tumor formation, and inhibition of viral replication. TNF-α and its receptors are ubiquitously expressed in developing organs and they regulate the survival, proliferation, and apoptosis of embryonic stem cells (ESCs) and progenitor cells. TNF-α is an important inflammatory factor that also regulates the inflammatory response during organogenesis, and its cytotoxic effects can interfere with normal developmental processes, even leading to the onset of diseases. This review summarizes the various roles of TNF-α in organogenesis in terms of its secreting pattern, concentration-dependent activities, and interactions with other signaling pathways. We also explored new potential functions of TNF-α.

Environmental enrichment alters neurobehavioral development following maternal immune activation in mice offspring with epilepsy

Epilepsy is a chronic brain disease affecting millions of people worldwide. Anxiety-related disorders and cognitive deficits are common in patients with epilepsy. Previous studies have shown that maternal infection/immune activation renders children more vulnerable to neurological disorders later in life. Environmental enrichment has been suggested to improve seizures, anxiety, and cognitive impairment in animal models. The present study aimed to explore the effects of environmental enrichment on seizure scores, anxiety-like behavior, and cognitive deficits following maternal immune activation in offspring with epilepsy. Pregnant mice were treated with lipopolysaccharides-(LPS) or vehicle, and offspring were housed in normal or enriched environments during early adolescence to adulthood. To induce epilepsy, adult male and female offspring were treated with Pentylenetetrazol-(PTZ), and then anxiety-like behavior and cognitive functions were assessed. Tumor-necrosis-factor (TNF)-α and interleukin (IL) 10 were measured in the hippocampus of offspring. Maternal immune activation sex-dependently increased seizure scores in PTZ-treated offspring. Significant increases in anxiety-like behavior, cognitive impairment, and hippocampal TNF-α and IL-10 were also found following maternal immune activation in PTZ-treated offspring. However, there was no sex difference in these behavioral abnormalities in offspring. Environmental enrichment reversed the effects of maternal immune activation on behavioral and inflammatory parameters in PTZ-treated offspring. Overall, the present findings highlight the adverse effects of prenatal maternal immune activation on seizure susceptibility and psychiatric comorbidities in offspring. This study suggests that environmental enrichment may be used as a potential treatment approach for behavioral abnormalities following maternal immune activation in PTZ-treated offspring.

Continuous exposure to amorphous formula of curcumin from the developmental stage facilitates anti-anxiety-like behavior and fear-extinction learning in rats

An amorphous formula of curcumin (CUR) has shown to enable an improved bioavailability after ingestion. The aim of this study was to investigate the hypothesis that exogenously administered CUR has an advantage in ameliorating post-traumatic stress disorder at low doses. To this end, Long-Evans rats were dietary exposed to CUR at 0.1% or 0.5% from gestational day 6 to postnatal day (PND) 74 or 77. Offspring exposed to 0.1% CUR revealed facilitation of anti-anxiety-like behavior in the open field test and fear-extinction learning tested during PND 62 to 74, increases in hippocampal granule cells expressing immediate-early gene proteins and a decrease in prelimbic cortical neurons expressing phosphorylated extracellular signal-regulated kinase 1/2 after the last trial of the fear-extinction learning test on PND 74. The constitutive gene expression levels of Gria1, Gria2, Grin2d, Slc17a6, and Slc17a7 were altered in the hippocampal dentate gyrus and amygdala on PND 77. These results suggest alterations in synaptic plasticity to strengthen neural circuits in promoting the behavioral effects by 0.1%-CUR. In contrast, 0.5% CUR revealed a lack of any of the changes in behavioral tests that were observed at 0.1%; however, this dose upregulated oxidative stress and neuroinflammation-related genes in the hippocampal dentate gyrus, and increased neural stem cells and proliferation activity of the subgranular zone in the dentate gyrus. These results suggest a possible preventive use of CUR at low doses in mitigating some stress disorders; however, excessively absorbed doses may prevent behavioral changes by inducing neuroinflammation that affects hippocampal neurogenesis involving neural stem cells.

Inflammation: A Proposed Intermediary Between Maternal Stress and Offspring Neuropsychiatric Risk

During pregnancy, programming of the fetal central nervous system establishes vulnerabilities for emergence of neuropsychiatric phenotypes later in life. Psychosocial influences during pregnancy, such as stressful life events and chronic stress, correlate with offspring neuropsychiatric disorders and inflammation, respectively. Stress promotes inflammation, but the role of inflammation as a mediator between maternal psychosocial stress and offspring neuropsychiatric outcomes has not been extensively studied in humans. This review summarizes clinical evidence linking specific types of stress to maternal inflammatory load during pregnancy. We propose that inflammation is a mediator in the relationship between psychosocial stress and offspring neuropsychiatric outcomes, potentially influenced by poor maternal glucocorticoid-immune coordination. We present relevant experimental animal research supporting this hypothesis. We conclude that clinical and preclinical research supports the premise that stress-induced maternal immune activation contributes in part to prenatal programming of risk. Programming of risk is likely due to a combination of vulnerabilities, including multiple or repeated inflammatory events; timing of such events; poor maternal regulation of inflammation; genetic vulnerability; and lifestyle contributors.

Understanding the Role of Antiviral Cytokines and Chemokines on Neural Stem/Progenitor Cell Activity and Survival

Viral infections of the central nervous system are accompanied by the expression of cytokines and chemokines that can be critical for the control of viral replication in the brain. The outcomes of cytokine/chemokine signaling in neural cells vary widely, with cell-specific effects on cellular activity, proliferation, and survival. Neural stem/progenitor cells (NSPCs) are often altered during viral infections, through direct infection by the virus or by the influence of immune cell activity or cytokine/chemokine signaling. However, it has been challenging to dissect the contribution of the virus and specific inflammatory mediators during an infection. In addition to initiating an antiviral program in infected NSPCs, cytokines/chemokines can induce multiple changes in NSPC behavior that can perturb NSPC numbers, differentiation into other neural cells, and migration to sites of injury, and ultimately brain development and repair. The focus of this review was to dissect the effects of common antiviral cytokines and chemokines on NSPC activity, and to consider the subsequent pathological consequences for the host from changes in NSPC function.

Maternal prenatal depression predicts infant negative affect via maternal inflammatory cytokine levels

Maternal depressive symptoms during pregnancy are associated with risk for offspring emotional and behavioral problems, but the mechanisms by which this association occurs are not known. Infant elevated negative affect (increased crying, irritability, fearfulness, etc.) is a key risk factor for future psychopathology, so understanding its determinants has prevention and early intervention potential. An understudied yet promising hypothesis is that maternal mood affects infant mood via maternal prenatal inflammatory mechanisms, but this has not been prospectively examined in humans. Using data from a pilot study of women followed from the second trimester of pregnancy through six months postpartum (N = 68) our goal was to initiate a prospective study as to whether maternal inflammatory cytokines mediate the association between maternal depressive symptoms and infant offspring negative affect. The study sample was designed to examine a broad range of likely self-regulation and mood-regulation problems in offspring; to that end we over-selected women with a family history or their own history of elevated symptoms of attention-deficit/hyperactivity disorder. Results supported the hypothesis: maternal pro-inflammatory cytokines during the third trimester (indexed using a latent variable that included plasma interleukin-6, tumor necrosis factor-alpha and monocyte chemoattractant protein-1 concentrations as indicators) mediated the effect, such that higher maternal depressive symptoms were associated with higher maternal inflammation, and this mediated the effect on maternal report of infant negative affect (controlling for maternal affect during the infant period). This is the first human study to demonstrate that maternal inflammatory cytokines mediate the association between prenatal depression and infant outcomes, and the first to demonstrate a biological mechanism through which depressive symptoms impact infant temperament.

Using immunocompromised mice to identify mechanisms of Zika virus transmission and pathogenesis

Zika virus (ZIKV) is responsible for a recent global epidemic that has been associated with congenital brain malformations in fetuses and with Guillain-Barré syndrome in adults. Within the last 2 years, a major effort has been made to develop murine models to study the mechanism of viral transmission, pathogenesis and the host immune response. Here, we discuss the findings from these models regarding the role that the innate and adaptive immune responses have in controlling ZIKV infection and pathogenesis. Additionally, we examine how innate and adaptive immune responses influence sexual and vertical transmission of ZIKV infection as well as how these responses can influence the ability of ZIKV to cross the placenta and to induce damage in the developing brain.

Infliximab ameliorating depression-like behavior through inhibiting the activation of the IDO-HAAO pathway mediated by tumor necrosis factor-α in a rat model

In recent years, some studies have suggested that the activation of inflammatory system plays a role in the occurrence of depression. Tumor necrosis factor-α (TNF-α), as one of the preinflammatory cytokines, has been reported to be involved in the occurrence of various diseases including depression. Infliximab, an antagonist of TNF-α, is usually used to treat some autoimmune diseases such as Crohn's disease and can perhaps be used to treat other diseases. In this study, the antidepressant effect and a possible mechanism of infliximab were investigated by studying the depression-like behavior and expression of TNF-α, indoleamine 2, 3-dioxygenase (IDO), and 3-hydroxyl amino acid oxygenase (HAAO) from the cortex and hippocampus in rat exposed to chronic unpredicted stress. Forty male Sprague-Dawley rats were divided into a control group (CG), an infliximab-treated control group, a model group (MG), and an infliximab-treated model group (IFXM). Infliximab (5 mg/kg once week) was administered to the infliximab-treated control group and IFXM rats by an intraperitoneal injection, whereas an equivalent volume of vehicle was administered to CG and MG rats. Rat behaviors and the expression of TNF-α, IDO, and HAAO in the cortex and hippocampus were determined. It was found that a significant relief in depression-like behaviors was observed with a downregulation of TNF-α, IDO, and HAAO expression in the IFXM rats compared with MG rats. The results show the antidepressant effect of infliximab and suggest that its mechanism is partly related to inhibition of IDO-HAAO pathway activation mediated by TNF-α in rat brain.

Effects of early-life adversity on immune function are mediated by prenatal environment: Role of prenatal alcohol exposure

The contribution of the early postnatal environment to the pervasive effects of prenatal alcohol exposure (PAE) is poorly understood. Moreover, PAE often carries increased risk of exposure to adversity/stress during early life. Dysregulation of immune function may play a role in how pre- and/or postnatal adversity/stress alters brain development. Here, we combine two animal models to examine whether PAE differentially increases vulnerability to immune dysregulation in response to early-life adversity. PAE and control litters were exposed to either limited bedding (postnatal day [PN] 8-12) to model early-life adversity or normal bedding, and maternal behavior and pup vocalizations were recorded. Peripheral (serum) and central (amygdala) immune (cytokines and C-reactive protein - CRP) responses of PAE animals to early-life adversity were evaluated at PN12. Insufficient bedding increased negative maternal behavior in both groups. Early-life adversity increased vocalization in all animals; however, PAE pups vocalized less than controls. Early-life adversity reduced serum TNF-α, KC/GRO, and IL-10 levels in control but not PAE animals. PAE increased serum CRP, and levels were even higher in pups exposed to adversity. Finally, PAE reduced KC/GRO and increased IL-10 levels in the amygdala. Our results indicate that PAE alters immune system development and both behavioral and immune responses to early-life adversity, which could have subsequent consequences for brain development and later life health.

Urinary Levels of IL-1β and GDNF in Preterm Neonates as Potential Biomarkers of Motor Development: A Prospective Study

Objectives. To evaluate the association between inflammatory biomarkers, neurotrophic factors, birth conditions, and the presence of motor development abnormalities in preterm neonates. Methods. Plasma and urinary levels of cytokines (IL-1β, IL-6, IL-10, TNF, and IL-12p70), chemokines (CXCL8/IL-8, CCL2/MCP-1, CCL5/RANTES, CXCL10/IP-10, and CXCL9/MIG), and neurotrophic factors (BDNF and GDNF) were evaluated in 40 preterm neonates born between 28 and 32 incomplete weeks of gestation, at four distinct time points: at birth (umbilical cord blood) (T0), at 48 (T1), at 72 hours (T2), and at 3 weeks after birth (T3). Biomarkers levels were compared between different time points and then associated with Test of Infant Motor Performance (TIMP) percentiles. Results. Maternal age, plasma, and urinary concentrations of inflammatory molecules and neurotrophic factors were significantly different between groups with normal versus lower than expected motor development. Higher levels of GDNF were found in the group with lower than expected motor development, while IL-1β and CXCL8/IL-8 values were higher in the group with typical motor development. Conclusion. Measurements of cytokines and neurotrophic factors in spot urine may be useful in the follow-up of motor development in preterm neonates.

Elevated Thyroid Peroxidase Antibody Increases Risk of Post-partum Depression by Decreasing Prefrontal Cortex BDNF and 5-HT Levels in Mice

Post-partum depression (PPD) is a common mental disease in the perinatal period that profoundly affects mothers and their offspring. Some clinical studies have found that PPD is related to thyroid peroxidase antibodies (TPOAbs); however, the mechanism underlying this relationship is unclear. Female C57BL/6 mice immunized with adenovirus encoding the cDNA of the full-length mTPO (mTPO-Ad) were used to establish the isolated TPOAb-positive mouse model in the present study. Maternal depressive-like behaviors were assessed using the forced swimming test (FST), sucrose preference test (SPT), and tail suspension test (TST) post-partum. The serum TPOAb titer was measured by enzyme-linked immunosorbent assay (ELISA) before pregnancy and post-partum. Furthermore, in the prefrontal cortex, the mRNA and protein expression levels of brain-derived neurotrophic factor (BDNF) were measured, serotonin (5-HT) levels were measured by ultra-high-performance liquid chromatography–tandem mass-spectrometry (UHPLC–MS/MS), and total thyroxine (TT4) levels were determined by ELISA. Compared with the controls, the mice immunized with mTPO-Ad displayed depressive behaviors, with a significantly lower sucrose preference (SP) at the 12-h time point and a longer immobility time in the FST and TST, which were accompanied by a lower expression of BDNF and 5-HT but no change in the TT4 concentration in the prefrontal cortex. Together, these findings suggest that elevated TPOAb may increase the risk of subsequent PPD and decrease the concentration of BDNF and 5-HT in the prefrontal cortex.

The immune system as a novel regulator of sex differences in brain and behavioral development

Sexual differentiation of the brain occurs early in life as a result of sex-typical hormone action and sex chromosome effects. Immunocompetent cells are being recognized as underappreciated regulators of sex differences in brain and behavioral development, including microglia, astrocytes, and possibly other less well studied cell types, including T cells and mast cells. Immunocompetent cells in the brain are responsive to steroid hormones, but their role in sex-specific brain development is an emerging field of interest. This Review presents a summary of what is currently known about sex differences in the number, morphology, and signaling profile of immune cells in the developing brain and their role in the early-life programming of sex differences in brain and behavior. We review what is currently known about sex differences in the response to early-life perturbations, including stress, inflammation, diet, and environmental pollutants. We also discuss how and why understanding sex differences in the developing neuroimmune environment may provide insight into understanding the etiology of several neurodevelopmental disorders. This Review also highlights what remains to be discovered in this emerging field of developmental neuroimmunology and underscores the importance of filling in these knowledge gaps. © 2016 Wiley Periodicals, Inc.

TNF-α concentrations in pre-operative synovial fluid for predicting early post-operative function and pain after fast-track total knee arthroplasty

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) helps regulate neuroinflammation and anxiety and could conceivable predict early post-operative pain and function after fast-track total knee arthroplasty (TKA).

METHODS

In patients with severe osteoarthritic knees undergoing TKA, we assessed: the correlations between pre-operative concentrations of TNF-α in synovial fluid; pre- and six-week post-operative knee function and pain; pre- and post-operative anxiety; pre- and post-operative synovial fluid concentrations of cartilage oligomeric matrix protein (COMP); age and body mass index (BMI).

RESULTS

Of 100 enrolled patients, 78 had evaluable TNF-α data, and 58 had evaluable COMP data. Pre-operative TNF-α concentrations were inversely correlated with post-operative pain scores during walking (r_S=-0.26, P=0.03) and with change of pain at rest during six weeks after TKA (r_s=-0.28, P=0.03) and were directly correlated with a higher post-operative Knee Society score (KSS) (r_S=0.43, P<0.001) and with greater increases in this score during six weeks after TKA (r_S=0.33, P=0.001). Mean TNF-α concentrations were higher in the 39 patients reporting any pre-operative pain at rest than in 36 patients reporting no pre-operative pain (P=0.015) and were the only independent predictor of pre-operative pain at rest (OR=13, P=0.02). Independent predictors of better post-operative knee function were higher log-transformed TNF-α concentrations (β=0.38, P=0.002) and male sex (β=0.28, P=0.02).

CONCLUSIONS

High levels of pre-operative TNF-α concentrations could be used as an independent predictor of better knee function at six weeks of follow-up. In patients with lower pre-operative TNF-α concentrations, post-operative pain management may improve the early outcome of the operated joint.

Maternal separation activates microglial cells and induces an inflammatory response in the hippocampus of male rat pups, independently of hypothalamic and peripheral cytokine levels

Adult animals subjected to chronic stress show an inflammatory response in the hippocampus which has been related to cognitive dysfunction and psychopathology. However the immediate consequences of early life stress on hippocampal glial cells have not been studied. Here we analyzed the effects of maternal separation (MS) on astrocyte and microglial cell morphology in the hippocampal hilus, compared the expression of cytokines in the hippocampus and hypothalamus, and the peripheral response of cytokines, on postnatal day (PD) 15. Male rat pups of MS (3h/day, PD1-PD14) and Control (CONT) pups showed similar microglial cell densities in the hilus, but MS pups presented more activated microglia. MS decreased astrocyte density and the number of processes in the hilus. Cytokine mRNA expression (qPCR) was analyzed in MS and CONT groups, sacrificed (i) under basal (B) conditions or (ii) after a single stress event (SS) at PN15. In hippocampal extracts, MS increased IL-1β mRNA, under B and SS conditions while IL-6 and TNF-α did not change. In hypothalamic tissue, MS increased TNF-α and IL-6 mRNA, but not IL-1b, after SS. Peripheral concentrations of IL-1β were decreased under B and SS conditions in MS; IL-6 concentration increased after SS in MS pups, and TNF-α concentration was unchanged. In conclusion, MS activates microglial cells and decreases astrocyte density in the hippocampus. A differential cytokine expression is observed in the hippocampus and the hypothalamus after MS, and after SS. Also, MS triggers an independent response of peripheral cytokines. These specific responses together could contribute to decrease hippocampal neurogenesis and alter the neuroendocrine axis.

Association Between Prenatal Exposure to Maternal Infection and Offspring Mood Disorders: A Review of the Literature

The purpose of this article is to provide a systematic review of studies that have examined the association between prenatal exposure to maternal infection and development of mood disorders across the life course. Drawing from both human- and animal-based studies, we give an overview of hypothesized biological mechanisms by which exposure to maternal infection during critical periods of gestation may contribute to fetal programming of mood disorders in offspring. We discuss studies examining the association between prenatal exposure to maternal infection with pathogens including influenza as well as other respiratory viruses, herpesviruses, hepatitis viruses, and Toxoplasma gondii and mood disorders in human populations. Moreover, we outline strengths and limitations of the current body of evidence and make recommendations for future research. We also discuss findings in the context of well-documented gender and socioeconomic disparities in the prevalence and severity of mood disorders, particularly major depression, and the role that early exposure to infection may play in explaining the perpetuation of such disparities across generations. Overall, this review of the current knowledge on this topic has important implications for determining future research directions, designing interventions as well as prenatal care guidelines targeted at prevention or treatment of infection during pregnancy, and clinical practice for the identification of individuals that may be at increased risk for mood disorders beginning early in life. Importantly, such efforts may not only lower the overall burden of mood disorders but also serve to address social disparities in these adverse mental health conditions in the U.S.

Activation of GABA-A receptors during postnatal brain development increases anxiety- and depression-related behaviors in a time- and dose-dependent manner in adult mice

Disturbances of the gamma-amino butyric acid-ergic (GABAergic) system during postnatal development can have long-lasting consequences for later life behavior, like the individual's response to stress. However, it is unclear which postnatal windows of sensitivity to GABA-ergic modulations are associated with what later-life behavioral outcomes. Therefore, we sought to determine whether neonatal activation of the GABA-A receptor during two postnatal periods, an early window (postnatal day 3-5) and a late window (postnatal day 14-16), can affect anxiety- and depression-related behaviors in male mice in later life. To this end, mice were treated with either saline or muscimol (50, 100, 200, 300 and 500μg/kg) during the early and late postnatal periods. An additional group of mice was treated with the GABA-A receptor antagonist bicuculline+muscimol. When grown to adulthood male mice were exposed to behavioral tests to measure anxiety- and depression-related behaviors. Baseline and stress-induced corticosterone (CORT) levels were also measured. The results indicate that early postnatal and to a lesser extent later postnatal exposure to the GABA-A receptor agonist muscimol increased anxiety-like behavior and stress-induced CORT levels in adults. Moreover, the early postnatal treatment with muscimol increased depression-like behavior with increasing baseline CORT levels. The anxiogenic and depression-like later-life consequences could be antagonized by bicuculline. Our findings suggest that GABA-A receptor signaling during early-life can influence anxiety- and depression-related behaviors in a time- and dose-dependent manner in later life. Our findings help to increase insight in the developmental mechanisms contributing to stress-related disorders.

Prenatal maternal immune activation increases anxiety- and depressive-like behaviors in offspring with experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is thought to result from a combination of genetics and environmental factors. Several lines of evidence indicate that significant prevalence of anxiety and depression-related disorders in MS patients can influence the progression of the disease. Although we and others have already reported the consequences of prenatal maternal immune activation on anxiety and depression, less is known about the interplay between maternal inflammation, MS and gender. We here investigated the effects of maternal immune activation with Poly I:C during mid-gestation on the progression of clinical symptoms of experimental autoimmune encephalomyelitis (EAE; a mouse model of MS), and then anxiety- and depressive-like behaviors in non-EAE and EAE-induced offspring were evaluated. Stress-induced corticosterone and tumor necrosis factor-alpha (TNF-α) levels in EAE-induced offspring were also measured. Maternal immune activation increased anxiety and depression in male offspring, but not in females. This immune challenge also resulted in an earlier onset of the EAE clinical signs in male offspring and enhanced the severity of the disease in both male and female offspring. Interestingly, the severity of the disease was associated with increased anxiety/depressive-like behaviors and elevated corticosterone or TNF-α levels in both sexes. Overall, these data suggest that maternal immune activation with Poly I:C during mid-pregnancy increases anxiety- and depressive-like behaviors, and the clinical symptoms of EAE in a sex-dependent manner in non-EAE or EAE-induced offspring. Finally, the progression of EAE in offspring seems to be linked to maternal immune activation-induced dysregulation in neuro-immune-endocrine system.

The interplay of early-life stress, nutrition, and immune activation programs adult hippocampal structure and function

Early-life adversity increases the vulnerability to develop psychopathologies and cognitive decline later in life. This association is supported by clinical and preclinical studies. Remarkably, experiences of stress during this sensitive period, in the form of abuse or neglect but also early malnutrition or an early immune challenge elicit very similar long-term effects on brain structure and function. During early-life, both exogenous factors like nutrition and maternal care, as well as endogenous modulators, including stress hormones and mediator of immunological activity affect brain development. The interplay of these key elements and their underlying molecular mechanisms are not fully understood. We discuss here the hypothesis that exposure to early-life adversity (specifically stress, under/malnutrition and infection) leads to life-long alterations in hippocampal-related cognitive functions, at least partly via changes in hippocampal neurogenesis. We further discuss how these different key elements of the early-life environment interact and affect one another and suggest that it is a synergistic action of these elements that shapes cognition throughout life. Finally, we consider different intervention studies aiming to prevent these early-life adversity induced consequences. The emerging evidence for the intriguing interplay of stress, nutrition, and immune activity in the early-life programming calls for a more in depth understanding of the interaction of these elements and the underlying mechanisms. This knowledge will help to develop intervention strategies that will converge on a more complete set of changes induced by early-life adversity.

The Involvement of TNF-α in Cognitive Dysfunction Associated with Major Depressive Disorder: An Opportunity for Domain Specific Treatments

Major depressive disorder is a highly prevalent, chronic and recurring disorder, associated with substantial impairment in cognitive and interpersonal functions. Accumulating evidence suggests that inflammatory processes play an important role in the etio-pathogenesis, phenomenology, comorbidity and treatment of MDD. Suboptimal remission rates and the persistence of cognitive deficits contribute to functional impairment in MDD inviting the need for the development of mechanistically novel and domain specific treatment approaches. The MEDLINE/ Pubmed database was searched from inception to February, 9th, 2014 with combinations of the following search terms: 'TNF-alpha', 'depression', 'infliximab', 'etanercept', 'adalimumab', 'golimumab' and 'certolizumab'. Preclinical and clinical evidence linking TNF-α to MDD pathophysiology were reviewed as well as the current status of TNF-α modulators as novel agents for the treatment of MDD. Experimental models and clinical studies provide encouraging preliminary evidence for the efficacy of TNF- α antagonists in mitigating depressive symptoms and improving cognitive deficits. Further studies are warranted to confirm these data in larger randomized controlled trials in primary psychiatric populations. Translational research provides a promising perspective that may aid the development and/or repurposing of mechanism-based treatments for depressive symptoms and cognitive impairment in MDD.

The importance of cytokines and autoantibodies in depression

The relationship between depression and immunity has been widely discussed. Cytokines, such as TNF-α, play an important role in immune system; these cytokines interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. Antibodies have also been implicated in the pathophysiology of depression. The association between decreased serotonin levels and excessive glutamatergic activity forms the first biochemical basis for cytokine-induced depression. Cytokines and antibodies (anti-ribosomal-P and anti-N-methyl-D-aspartate receptor antibodies) are deeply related to pathogenesis of neurodevelopmental disorders, especially depression. Tumor necrosis factor alpha (TNF-α) may underlie the mechanism of depression by an activation of the hypothalamo-pituitary-adrenocortical (HPA) axis, an activation of neuronal serotonin transporters and the stimulation of the indoleamine 2,3-dioxygenase which leads to tryptophan depletion. In the last 20 years since the initial reports of neural-immune interactions in depression, studies have shown a clear association between activation of the immune system mediated by proinflammatory cytokines. Genes encoding cytokines are highly polymorphic and single nucleotide polymorphisms, associated with increased or reduced cytokine production, have been described. To date, there are only few studies that investigated the relationship between depression and proinflammatory cytokines in patients with autoimmune diseases. Although an associative link between neuroinflammation and mood disorders is widely accepted, further studies are necessary to establish the cause-effect relationship. In this paper, we review the role of cytokines, focusing on TNF-α and antibodies in the depression and hypothesize how TNF-α may underlie and mediate the inflammatory process depression in patients with autoimmune disease.